dpdk: fix cryptodev offset update

Type: fix

This patch fixes the missed crypto and integ offset update for
every packet. Previously the offset is updated only when the
key is changed. This is ok for encryption but not always true
for decryption.

Signed-off-by: Fan Zhang <roy.fan.zhang@intel.com>
Change-Id: Iccd0011f4ae488746ce487a14b94ddd24fb0c07c